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<table class="index-toc-link"><tr><td class="left">[<a href="ft2-index.html">Index</a>]</td><td class="right">[<a href="ft2-toc.html">TOC</a>]</td></tr></table>
<h1>FreeType-2.6.2 API Reference</h1>

<h1 id="error_enumerations">Error Enumerations</h1>

<p>The header file &lsquo;fterrors.h&rsquo; (which is automatically included by &lsquo;freetype.h&rsquo; defines the handling of FreeType's enumeration constants. It can also be used to generate error message strings with a small macro trick explained below.</p>
<p><b>Error</b> <b>Formats</b></p>
<p>The configuration macro FT_CONFIG_OPTION_USE_MODULE_ERRORS can be defined in &lsquo;ftoption.h&rsquo; in order to make the higher byte indicate the module where the error has happened (this is not compatible with standard builds of FreeType&amp;nbsp;2, however). See the file &lsquo;ftmoderr.h&rsquo; for more details.</p>
<p><b>Error</b> <b>Message</b> <b>Strings</b></p>
<p>Error definitions are set up with special macros that allow client applications to build a table of error message strings. The strings are not included in a normal build of FreeType&amp;nbsp;2 to save space (most client applications do not use them).</p>
<p>To do so, you have to define the following macros before including this file.</p>
<pre class="colored">
  FT_ERROR_START_LIST                                               
</pre>
<p>This macro is called before anything else to define the start of the error list. It is followed by several FT_ERROR_DEF calls.</p>
<pre class="colored">
  FT_ERROR_DEF( e, v, s )                                           
</pre>
<p>This macro is called to define one single error. &lsquo;e&rsquo; is the error code identifier (e.g., &lsquo;Invalid_Argument&rsquo;), &lsquo;v&rsquo; is the error's numerical value, and &lsquo;s&rsquo; is the corresponding error string.</p>
<pre class="colored">
  FT_ERROR_END_LIST                                                 
</pre>
<p>This macro ends the list.</p>
<p>Additionally, you have to undefine &lsquo;__FTERRORS_H__&rsquo; before #including this file.</p>
<p>Here is a simple example.</p>
<pre class="colored">
  #undef __FTERRORS_H__                                             
  #define FT_ERRORDEF( e, v, s )  { e, s },                         
  #define FT_ERROR_START_LIST     {                                 
  #define FT_ERROR_END_LIST       { 0, NULL } };                    
                                                                    
  const struct                                                      
  {                                                                 
    int          err_code;                                          
    const char*  err_msg;                                           
  } ft_errors[] =                                                   
                                                                    
  #include FT_ERRORS_H                                              
</pre>
<p>Note that &lsquo;FT_Err_Ok&rsquo; is <i>not</i> defined with &lsquo;FT_ERRORDEF&rsquo; but with &lsquo;FT_NOERRORDEF&rsquo;; it is always zero.</p>

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